James "Whitey" Bulger was captured on June 22, 2011, in Santa Monica, Calif. / AP

by G. Jeffrey MacDonald, Special for USA TODAY

by G. Jeffrey MacDonald, Special for USA TODAY

BOSTON - In their first day of deliberations Tuesday, jurors were unable to reach a verdict on the racketeering charges against alleged Boston mob boss James "Whitey" Bulger.

After six hours, Judge Denise Casper dismissed the jury, which will return to court Wednesday morning. They'll again ponder the 32-count indictment that implicates Bulger with money laundering, extortion and 19 murders in a two-decade reign as leader of the notorious Winter Hill gang.

Earlier Tuesday, Casper, in instructions that lasted nearly three hours, told jurors not to base judgment on the fact that Bulger, 83, declined to testify. That's his constitutional right, Casper said.

She also told jurors that they may take into account how plea deals with the government might have impacted testimony from certain witnesses. Each of the three key witnesses in the trial â?? John Martorano, Kevin Weeks and Stephen "The Rifleman" Flemmi â?? has received benefits in exchange for agreeing to testify against Bulger.

The 83-year-old had fled Boston and eluded authorities for 16 years until he was arrested in Santa Monica, Ca., in 2011.

Often gruesome testimony in Bulger's trial portrayed him as an active participant in several slayings.

As they wrapped closing arguments, prosecutors called Bulger one of the worst criminals in U.S. history.

But Bulger's defense team said the government's key witnesses were pathological liars who had cut deals to reduce prison time - or worse.

Flemmi pleaded guilty to 10 murders, but escaped the death sentence. Martorano, who admitted murdering 20 people, served just 12 years behind bars. Weeks, released after serving five years, previously admitting to being an accessory to several murders.